Best thickness for metal to blank out windows on MC9?

[ilyafish]

The subject says it all haha

[Sojourner]

5052 aluminum is great for structural and blanking metal.

For window cut-out use .090 inch thick.

For blanking or non window cut-out use .060 inch. You can use it for window cut-out but becareful not strip screw to mount window unless a metal framing behind it.

What your plan for skin's fastners?

Sojourn for Christ, Gerald

[Tom Y]

What about the alumium with plastic sandwiched between? Used for buildings and closing in bigger windows. Its about 5/16 thick but I can check.   Tom Y

[Sojourner]

What about the alumium with plastic sandwiched between? Used for buildings and closing in bigger windows. Its about 5/16 thick but I can check.   Tom Y

Thank you for the suggestion. Could you post a link of this product? I too would like learn more.

Thanks, Gerald

[ilyafish]

Gerald, i was considering of welding. Though if its aluminum i might have a problem so i was considering of using standard steel.

[TomCat]

My Thomas is built from 20ga cold rolled steel, so when it came time to cover the windows, I used...you guessed it...20ga CRS.

HTH

Jay
87 SaftLiner

[Hobe]

20 gage Pant gripe galvenized steel is about as good as you can get . It is about the same weight bas 80 or 90 Alum. , Will not stretch as much in hot weather. And is half the price. I have skinned over 100 buses in the past 25 years. If you want to see what they look like Google my name Fred Hobe.

[Tom Y]

Gerald, It does not have a name on it. I just have some small pieces around here. It has been out for a while now. It is 1/4 thick and very strong. Here is a pic. There is a plastic film on one side.   Tom Y

[Sojourner]

About using CRS (cold roll steel) sheet metal 20 ga. which is .035" thick.

Plug Welds

BTW...a newer mig weld wire called Easy Grind is best for application. I never heard of this until now but it soft and easy to grind.
All-State Easy Grind

Whatever you do while welding...stagger your welding spots so it can cooled to avoid waves. Such as middle of both ends & top & bottom, diagonal both left & right corners and then in between holes left & right & top & bottom until all holes are plug welded. Don't rush.

You can spot-weld with mig but need at least 170 amps mig welder with notch nozzle. It compress the metal to the frame for tight bonding.
Mig Spot Welding

If you use galvanized steel metal and weld to framing...suggest plug-weld via predrilled panel with 5/16" holes. This will allow weld from ID of the hole (bare steel) to frame. Avoid inhaling the rising toxic smoke from burning galvanize coating at all cost.....dangerous.

BTW...Fred Hobe...Did you use rivets to install galvanize panels? If so... are you using solid aluminum or pull-through with mandrel or whatever? Thank you for your input.

FWIW

Sojourn for Christ, Gerald

[Sojourner]

Gerald, It does not have a name on it. I just have some small pieces around here. It has been out for a while now. It is 1/4 thick and very strong. Here is a pic. There is a plastic film on one side.   Tom Y

Thank you Tom Y.

That panel be good for wall strength but fastener will loosen during structural diagonal movement because of air gap.

It can be use elsewhere. If you ever locate the source of this panel, please let us know if you will.

Take care, Gerald

[Airbag]

I want to chime in. I don't wish to offend anyone but aluminum is my thing being an aircraft builder for most of my life.

I suggest that sandwich material if it is affordable and available. It should give the most rigidity with the least weight. It will however pose some chalanges with regards to fasteners and attachments.

If not 6061-T6 is a good affordable commercial alloy that will give fair rigidity in .063 and greater thicknesses and is weldable with a minimum bend radius that is not to large. It drills and cuts well without to much loading up of your cutters.

When drilling and using rotary files on aluminum try using a little wax on your cutters from a candle and you will find it keeps the flutes clear.

Everything you ever needed to know about working aluminum and riveting can be found in this document. Section 4.

http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/0/99c827db9baac81b86256b4500596c4e/$FILE/Chapter%2004.pdf

[ilyafish]

out of all of these, which is the cheapest route to go?

[Airbag]

Gerald, It does not have a name on it. I just have some small pieces around here. It has been out for a while now. It is 1/4 thick and very strong. Here is a pic. There is a plastic film on one side.   Tom Y

Thank you Tom Y.

That panel be good for wall strength but fastener will loosen during structural diagonal movement because of air gap.

It can be use elsewhere. If you ever locate the source of this panel, please let us know if you will.

Take care, Gerald

Hello Gerald
You are correct about the fasteners loosening, like I said in my prevous post there is some issues with the sandwich materials. However they make inserts that can be installed correcting this problem using a spot facer and adhesives  a standard practice in the aircraft industry but a major effort for the novice.

[Airbag]

out of all of these, which is the cheapest route to go?

6061-T6 (my opinion)

[Sojourner]

Thank you Rick for your valuable suggestion. I have click on your link at the bottom of your post a week ago and learn what you do. That great to have someone on board who is acknowledgeable about metal fabrication work in aircraft.

I have always put aluminum skin my first choice over steel version. However, you suggest 6061-T6 which is much harder metal and more expensively than 5052. Can I ask you why 6061-T6 your choice? I know what it is because I use it at GM Tech Center for many years. I do think that 5052 is harder to find than 6061-T6.
It make no difference to me which one to use, however I think that 5052 hold paint better.

Thanks, Rick
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out of all of these, which is the cheapest route to go?

iminaccess....the cost factor of either way is determine the length of time you own the bus. Aluminum & rivets cost more at front but none later. Steel and Galvanize metal with spot or plug welds is more prone to crack around hardness welded and it hard to keep it from rusting or galvanize have problem to keep paint on for a long time. If you hot spray foamed the interpanel to keep is from wind travel vibration, that will help the weld from fatigue around it.

You ever seen a steel skinned production bus without horizontal ribbing? That to keep panel from vibrating while traveling thorough wind. Example if you put a flag on pole out in open air in traveling...you will notices it waving aggressively. That what the sides of the long flat vehicle is happening but it design and build to withstand the waving wind going by via using ribbed thin sheet metal or thicker metal such as aluminum without ribbing. 

FWIW

Sojourn for Christ, Gerald